(...) Two of the plants will deploy parabolic troughs, or curved mirrors used to generate steam that in turn powers a turbine to produce electricity. The third plant will use a central tower receiver, where a field of mirrors reflects sun rays toward a water tower. As the water heats, it turns into steam, which can then be converted into electricity using a turbine.Torresol claims it will be the first commercial-scale deployment of a central tower receiver system. The three power plants are expected to have a total value of €800 million ($1.25 billion). Torresol also claims it will have 500 megawatts of concentrating solar projects by 2012.